The Lagos State Ministry of Health said four new cases of coronavirus have been confirmed in the case.
This brings to 12 the total number of coronavirus cases in Nigeria, although one of the victims has fully recovered.
The Commissioner for Health, Akin Abayomi, addressed journalists on the new cases on Thursday at the state secretariat.
He said 19 tests were performed on suspected cases and contacts of the five cases announced on Wednesday, out of which four turned positive.
The first positive test is that of a Nigerian female who returned from France via a Turkish airline (TK 1830) on March 14.
Another confirmed case is a Nigerian male in his 50s who had never travelled anywhere. He tested positive and had since been admitted.
Mr Abayomi said the third case is a Nigerian male who arrived in Nigeria on March 13, from Frankfurt, Germany on Luftansa flight LH 568.
"What we have is a combination of imported cases and local transmission," Mr Abayomi said.
He added that the ministry is currently tracking over 1,300 people in relation to Covid-19.